1. Field of the Invention
The present invention relates to sheet feeding apparatuses, such as automatic original feeding apparatuses, for feeding an original to an original table of, for example, an electronic copying machine.
2. Description of the Related Art
Some of the automatic original feeding apparatuses of this type have a function to turn over the original. These apparatuses comprise an original table for carrying the original. After the original is taken out by means of a pickup roller, it is separated from its successors by means of a pair of separating rollers. Then, the original is delivered to aligning rollers by means of feed rollers. After it is aligned by the aligning rollers, the original is fed to a conveyor belt. Thereupon, it is transported to a predetermined position on the original table to be set therein. In this state, one side of the original is copied. Subsequently, the original is removed from the original table by means of the conveyor belt, and is then discharged onto a receiving tray by means of feed rollers, exit guides, and exit rollers. In copying both sides of the original, the conveyor belt is rotated reversely after the end of the copying of the one side. As a result, the original is returned to the aligning rollers. A gate is provided between the original table and the aligning rollers. The original is guided to a turning mechanism by means of the gate. The turning mechanism includes a looped turn guide, used to guide the original from the gate to the upper-course side of the aligning rollers, and a plurality of guide rollers arranged along the turn guide. As the guide rollers rotate, the original is transported along the turn guide, whereby it is turned over and delivered to the aligning rollers. After it is aligned by means of the aligning rollers, the original is delivered to the conveyor belt. By the conveyor belt, the original is transported again to the original table to be set thereon. In this state, the other side of the original is copied. After the copying of both sides of the original is finished, the original is transported successively through the conveyor belt, feed rollers, and exit rollers, to be discharged onto the tray.
Since the turning mechanism is located on the supply side of the conveyor belt, the original must be transported for a long distance by the belt in order to be turned over. Thus, the time required for turning over the original is so long that the turning mechanism of this arrangement cannot be applied to high-speed machines.